Driving distance using Google Distance Matrix API

library(RCurl)
library(RJSONIO)
library(plyr)


distbase <- "http://maps.googleapis.com/maps/api/distancematrix/json?&origins="
url1 <- function(origin , destination , sep = "") {
 u2 <- paste(distbase, origin ,"&destinations=",
            destination ,"&mode=driving&units=imperial&language=EN&sensor=false")

 return(URLencode(u2))
}


drive <- function(origin, destination,verbose=FALSE) {
 if(verbose) cat(origin,destinaiton,"\n")
 u3 <- url1(origin,destination)
 doc <- getURL(u3)
 x <- fromJSON(doc,simplify = FALSE)
 if(x$status=="OK") {
  dist <- x$rows[[1]]$elements[[1]]$distance$text
  return(c(dist))
 } else {
  return(c(NA))
 }
}



###example
drive("new york ny", "chicago il")




#############################################################
############  ui.R

#library(shiny)

# Define UI for miles per gallon application
#shinyUI(pageWithSidebar(

# Application title
#  headerPanel("Miles Per Gallon"),

#  sidebarPanel(),

#  mainPanel()
#))



#library(shiny)

# Define UI for application that plots random distributions 
#shinyUI(pageWithSidebar(

# Application title
#  headerPanel("Hello Shiny!"),

# Sidebar with a slider input for number of observations
#  sidebarPanel(
#    sliderInput("obs", 
#              "Number of observations:", 
#                min = 0, 
#                max = 1000, 
#                value = 500)
#  ),

# Show a plot of the generated distribution
#  mainPanel(
#    plotOutput("distPlot")
#  )
#))


library(shiny)
shinyUI(pageWithSidebar(
 headerPanel("Calculate driving distances here!"),
 sidebarPanel(
  textInput("from_city", "From City", "") ,
  textInput("to_city", "To City", "") ,
  helpText("Note: Distances are calculated using Google Distance Matrix API"),
  
  submitButton("Calculate")
  
 ),



 mainPanel(
  
  h4 ("Driving Distance is:"),
  #verbatimTextOutput("text"),
  
  #h4 ("Cities"),
  #verbatimTextOutput("caption") ,
  
  #h4("Summary Final"),
  verbatimTextOutput("summary")
   
 )
))



########################################################################################################## server.R


library(RCurl)
library(RJSONIO)
library(plyr)
library(shiny)
shinyServer(function(input,output) {



 formulaText <- reactive({
  paste("Driving distance between", input$from_city,"and" , input$to_city )
 })

 funcInput <- reactive ({driving.distance(input$from_city, input$to_city)})


 output$text <- renderText({
  "foo bar"
 })

 output$caption <- renderText({
  formulaText()
 })

 output$summary <- renderText({
 funcInput()
 })


 })